An XYY boy with short stature and a case of Klinefelter's syndrome (XXY) in a family with inversion 9.

A patient with Klinefelter's syndrome and a boy with XYY sex chromosomes were both found to have a pericentric inversion of chromosome 9. An unusual feature of the XYY patient was that he presented because of short stature and disturbed behaviour. A family study showed that the patients were related and that there was an excess of males in the pedigree. Another member of the family was found to have some XYY cells in the blood.